Graphical user interface for a portion of a display screen



The FIGURE is a front view of a graphical user interface for a portion of a display screen showing a new design.

The broken line showing an outer border of the screen is included for the purpose of illustrating environmental structure and forms no part of the claimed design. All the text and graphics shown in white are shown in broken line and form no part of the claimed design. 

The ornamental design for a graphical user interface for a portion of a display screen, as shown and described. 